改性后不同孔隙度多孔钛对成骨细胞的影响

采用碱热处理和仿生沉积HA对注射成形多孔钛进行表面处理,研究改性后多孔钛的细胞毒性及其成骨细胞黏附、增殖和分化的影响。结果表明:改性后多孔钛无细胞毒性,不同孔隙度多孔钛的细胞黏附形貌不同,复合培养7d后,5%孔隙度组细胞平铺于材料表面,30%孔隙度组细胞多呈长梭形,60%孔隙度组MG63细胞伪足以锚状牢固附着于孔壁的颗粒之上,形成细胞桥;成骨细胞在高孔隙度组表面细胞的增殖数高于低孔隙度组表面细胞的;复合培养7d与14d,5%孔隙度组与30%孔隙度组的上清液中碱性磷酸酶(Alkaline phosphatase,ALP)含量无明显差别(p0.05),而60%孔隙度组的ALP含量高于低孔隙度组的。     

钛基体表面多级孔洞结构的制备和生物活性研究

目的通过调控钛基体表面的结构和特性,提高惰性钛基体表面的生物活性,改善其医用植入效果。方法采用碱热处理方法在钛基体表面构建多级孔洞结构,对改性后钛片的表面形貌、成分、结构、亲疏水性进行表征,评价钛片表面对类骨磷灰石的诱导能力。结果碱热处理使钛表面形成了多孔网状结构,孔洞包括微米级孔和200~300 nm的纳米孔,孔隙间隔介于微米至几百纳米之间。碱热处理后的钛片表面形成了含有大量羟基的氧化物层,主要成分为金红石型Ti O2和碱性钛酸盐,具有极好的亲水性,接触角仅约为12°。碱热处理钛片表面的三维多孔结构对磷灰石的生长有很好的诱导作用,矿化7天后,类骨磷灰石便完全覆盖表面,14天后的矿化效果更好。结论纯钛表面通过碱热处理法构建微纳多孔结构后,具有良好的诱导羟基磷灰石形成的能力,对其生物活性有促进作用。     

牙骨质基质提取物促成骨细胞在钛表面上粘附与移行的实验研究

选用表面光滑的金属钛片作为细胞粘附的底物，检测各时间点牙骨质基质提取物对成骨细胞在钛片上贴壁率的影响，并且运用图象分析法分析1，3，6d钛片周围成骨细胞的粘附指数和3，6d钛片周围成骨细胞的移行指数。结果显示：随牙骨质基质提取物作用时间的延长，成骨细胞的贴壁率不断上升，且牙骨质基质提取物无论是成骨细胞在钛片周围的粘附指数还是移行指数均明显高于对照组。因此为获得种植体与植骨床之间良好的骨结合界面，牙骨质基质提取物有可能作为种植体表面的生物涂层材料。     

多孔钛表面梯度磷灰石涂层的简单化学法制备

通过碱液处理或碱热处理并在模拟体液(SBF)中浸泡，在多孔钛表面制备了具有梯度结构的类骨磷灰石层。结果表明，碱液处理使多孔钛表面形成了网状多孔结构，组成为钛酸钠、金红石等。热处理后磷灰石在多孔钛表面的初期沉积更均匀。涂层中钙，磷、氧以及钛元素的含量随深度而变化，形成了梯度结构。具有表面梯度磷灰石涂层的多孔钛有望用于临床矫形，以提高种植体的生物活性和骨结合强度。     

钛表面预处理对溶胶-凝胶法制备羟基磷灰石涂层的影响

利用溶胶-凝胶法在工业纯钛表面制备羟基磷灰石（HA）涂层，探讨了酸洗和浓碱热处理两种基体预处理工艺对涂层的影响；用接触角仪测量了涂覆前两种预处理后基体的接触角并计算其表面能；用扫描电镜（SEM）、X射线衍射仪（XRD）分析了基体和涂层的表面、截面形貌及成分。结果表明：通过溶胶-凝胶法，在基体表面涂覆了HA涂层；与酸洗基体相比，浓碱热处理后在钛表面生成了网状多孔的钛酸钠水凝胶层，提高了基体的表面活性及表面能，由酸洗后的57．68mJ·m^-2增加到浓碱热处理后的77．34mJ·m^-2，尤其是极性色散比由0．235增至0．727，有利于HA在其表面涂覆，减少了提拉次数且HA涂层致密、厚度均匀约为3μm；提高了涂层与基体的结合力。     

不同介质溶液对多孔钛微观结构和力学性能的影响

采用钛网层叠烧结法制备出孔隙率为45%的多孔钛,研究酸洗处理、碱热处理、模拟体液浸泡中不同介质溶液对多孔钛表面微观结构和力学性能的影响规律。结果表明:酸洗处理在多孔钛表面形成"阶梯"型层状光滑表面,碱热处理在多孔钛表面形成微/纳米孔,模拟体液浸泡处理则在多孔钛表面形成均匀的羟基磷灰石涂层。在力学测试中,酸洗处理及碱热处理能显著地降低多孔钛的弹性模量,对于屈服强度则无显著影响;模拟体液浸泡处理则能显著提高多孔钛的杨氏模量和屈服强度。     

钛酸盐纳米线控制细胞的粘附及其活性

控制细胞与生物材料的互动在植入器械包括药物输送系统,生物感应器等方面的应用是非常渴望的。目前对于开发能够限制细胞的粘附以及活性的新材料有着较大的期待。通过水热法在钛片表面制作钛酸盐纳米线支架,研究了钛酸盐纳米线对MG63成骨细胞粘附、增殖、分化的影响。结果显示,与光滑组钛片比较在纳米线表面有较少的细胞粘附,扫描电镜观察可见仅有少量细胞被纳米线穿刺并固定在纳米线表面,并且细胞形态呈不规则的长条形,免疫荧光染色显示细胞不能形成细胞骨架并且细胞形状不规则;随后的细胞增殖也受到了明显的抑制;碱性磷酸酶以及RUNX2活性检测发现纳米线组细胞其分化能力也相应减弱。纳米线表面细胞早期粘附以及增殖及分化功能受到严重抑制。这种抗细胞粘附的纳米结构在药物缓释系统以及生物感应器等方面有应用价值。     

用碱性热处理和电化学沉积的复合技术在钛衬底上制备分层的羟磷灰石／钛酸钠生物陶瓷涂层

用三步工艺在经喷砂的钛衬底上制备了钛酸钠生物陶瓷涂层。第一步,经喷砂的钛衬底用碱性热处理涂上一层片状的钛酸钠层。第二步,碱性热处理的钛衬底是在180℃的热碱溶液中处理4h。第三步,用电化学沉积方法在热液中处理过的层上沉积羟磷灰石（HA）涂层。涂层的表面形貌和粗糙度分别用场发射扫描电子显微镜（FESEM）和机械接触表面光度仪观测。     

钛合金表面声电沉积／碱热处理法制备HA涂层研究

为了使钛合金（Ti-6Al-4V）具有生物活性，可在其表面施加生物活性羟基磷灰石（HA）涂层。对比了声电沉积法和碱热处理法实验结果，采用扫描电镜（SEM）、X射线衍射仪（XRD）、电子能谱（EDS）、傅立叶红外透射光谱（FTIR）以及划痕测试等进行了分析。结果表明，直接采用声电沉积法在钛合金表面制备的羟基磷灰石涂层，经热处理后存在龟裂剥落现象；通过碱热处理法，对钛合金基体表面进行预处理，然后，借助声电沉积法，在钛金属表面沉积了透钙磷石涂层，经热碱液处理转变成的羟基磷灰石涂层，涂层完整，未出现剥落。经进一步高温烧结处理，所制涂层仍呈片状形貌，其由部分含钠的羟基磷灰石组成，而且HA涂层破坏的临界载荷未烧结前的4．365N提高至烧结后的8．175N。     

CVI C／C复合材料及其表面HA涂层成骨细胞体外响应行为对比研究

采用声电化学工艺在CVI C／C复合材料表面制备了HA涂层，分别用SEM，XPS，EDAX和XRD表征了CVI C／C和HA的表面形貌、组成和结构，同时对比了成骨细胞在其表面的粘附、增殖和碱性磷酸酶活性的表达。制备的HA涂层为球状形貌，由纳米片状晶体构成。细胞培养初期，粘附于HA涂层表面的细胞数与CVI C／C表面的细胞数无显著差别，成骨细胞在CVI C／C表面易铺展在孔的边缘，8h后粘附于HA表面的成骨细胞数显著多于CVI C／C表面。HA涂层提高了细胞的增殖能力，成骨细胞碱性磷酸酶在HA涂层表面的表达也优于CVI C／C材料。结果表明，声电化学制备的HA涂层提高了CVI C／C材料的生物活性和生物相容性，可以加速成骨细胞的粘附、增殖、分化和成熟。成骨细胞在材料表面的粘附机制是由多因素综合作用的，材料的表面形貌和生物活性在细胞粘附过程的早期发挥着重要作用。     

多孔钛表面无裂纹生物活化层的制备及表征

采用碱热处理方法对多孔钛进行了表面活化处理,获得了无裂纹的网状微孔结构的生物活化层。利用扫描电镜(SEM)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)等设备对生物活化层进行表征,最后用模拟体液中浸泡的方法检测了该活化层的生物活性。结果表明:当NaOH溶液浓度低于8 mol/L,碱处理时间少于36 h时,多孔钛孔内外壁都可获得无裂纹的生物活化层,该活化层呈现网状微孔结构,是由金红石结构的二氧化钛和钛酸钠组成的混合物质。浸泡SBF后结果显示该活化层在浸泡3 d后就已诱导产生了类骨的碳羟基磷灰石,表现出了很好的生物活性。     

Bone integration properties of antibacterial biomimetic porous titanium implants

A novel antibacterial biomimetic porous titanium implant with good osseointegration was prepared by freeze-casting and thermal oxidation. Bone integration properties of the porous titanium implant were evaluated by cell proliferation assay, alkaline phosphatase activity assay, X-ray examination and hard bone tissue biopsy. The in vitro cell proliferation and the level of differentiation of the group with a modified nano-porous implant surface were significantly higher than those in the group without surface modification and the dense titanium control group (P<0.05). In vivo, bone growth and osteogenesis were found in the experimental groups with modified and unmodified porous titanium implants; osteoblasts in the modified group had more mature differentiation in the pores compared to the unmodified group. Such implants can form solid, biologically compatible bone grafts with bone tissues, exhibiting good osseointegration.     

Osteogenic composite nanocoating based on nanohydroxyapatite,strontium ranelate and polycaprolactone for titanium implants

Titanium and its alloys are commonly used as dental and bone implant materials. Biomimetic coating of titanium surfaces could improve their osteoinductive properties. In this work, we have developed a novel osteogenic composite nanocoating for titanium surfaces, which provides a natural environment for facilitating adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells (MSCs). Electrospinning was used to produce composite nanofiber coatings based on polycaprolactone (PCL), nano-hydroxyapatite (nHAp) and strontium ranelate (SrRan). Thus, four types of coatings, i.e., PCL, PCL/nHAp, PCL/SrRan, and PCL/nHAp/SrRan, were applied on titanium surfaces. To assess chemical, morphological and biological properties of the developed coatings, EDS, FTIR, XRD, XRF, SEM, AFM, in-vitro cytotoxicity and in-vitro hemocompatibility analyses were performed. Our findings have revealed that the composite nanocoatings were both cytocompatible and hemocompatible; thus PCL/HAp/SrRan composite nanofiber coating led to the highest cell viability. Osteogenic culture of MSCs on the nanocoatings led to the osteogenic differentiation of stem cells, confirmed by alkaline phosphatase activity and mineralization measurements. The findings support the notion that the proposed composite nanocoatings have the potential to promote new bone formation and enhance bone-implant integration.     

Preparation and in vitro biocompatibility of hybrid oxide layer on titanium surface

A new technique combining microarc oxidation (MAO) and electrophoresis was introduced to develop a biocompatible oxide layer on pure titanium implant surface. Originally developed alkaline electrolyte containing nano-scale hydroxyapatite powder suspension was used in the new technique. In the electric field, nano-scale hydroxyapatite powder was electrophoretically moved and sintered into the gradually-formed oxide layer on titanium anode. Physio-chemical properties and in vitro biological performance of the newly-formed surface were examined and evaluated. A 8.5-μm thick oxide layer with high surface energy and roughness, which was composed of titanium dioxide and calcium phosphates as well as hydroxyapatite, was formed on titanium surface by the modified MAO technique. Osteoblasts cultured on the modified MAO titanium surface showed significantly increased alkaline phosphatase (ALP) activity comparing to machined and MAO titanium surface. Natural oxide surface of titanium could be transformed into a hybrid oxide layer by modified MAO treatment. The modified titanium surface, which is rough and porous, contains calcium phosphates and proved to be more biocompatible in vitro.     

Electrochemical corrosion behavior and MG-63 osteoblast-like cell response of surface-treated titanium

Commercially pure titanium is used as a clinical implant material for many orthopedic and dental implant devices owing to its excellent corrosion resistance and good biocompatibility. However, there remains concern over the release of metal ions from prostheses and unresolved questions about its behavior in a biological environment. Our research investigated the influence of surface oxide thickness and phase on the corrosion resistance in 0.9% NaCl solution by potentiostat and XRD. Also, the MG-63 osteoblast like cell morphology and proliferation were studied to evaluate the biocompatibility in terms of surface treatment. It is demonstrated that a substantial decrease in the current density may be attained due to surface oxide thickening and phase transformation by thermal oxidation. The osteoblast adhesion morphology and proliferation data indicated that the osteoblast cell response is not conspicuously influenced by the thermal oxidation and nitric acid passivation treatments but by surface roughness and porosity of 3^rd networking.     

Development of osteoblast colonies on new bioactive coatings

The aging baby boomer population coupled with an increase in life expectancy is leading to a rising number of active elderly persons in occidental countries. As a result, the orthopedic implant industry is facing numerous challenges such as the need to extend implant life, reduce the incidence of revision surgery, and improve implant performance. This paper reports results of an investigation on the bioperformance of newly developed coating-substrate systems. Hydroxyapatite (HA) and nano-titania (nano-TiO₂) coatings were produced on Ti-6Al-4V and fiber reinforced polymer composite substrates. In vitro studies were conducted to determine the capacity of bioactive coatings developed to sustain osteoblast cells (fetal rat calvaria) adherence, growth, and differentiation. As revealed by scanning electron microscopy (SEM) observations and alkaline phosphatase activity, cell adhesion and proliferation demonstrated that HA coatings over a polymer composite are at least as good as HA coatings made over Ti-6Al-4V substrate in terms of osteoblast cell activity. Nano-TiO₂ coatings produced by high-velocity oxyfuel (HVOF) spraying led to different results. For short-term cell culture (4.5 and 24 h), the osteoblasts appeared more flattened when grown on nano-TiO₂ than on HA. The surface cell coverage after seven days of incubation was also more complete on nano-TiO₂ than HA. Preliminary results indicate that osteoblast activity after 15 days of incubation on nano-TiO₂ is equivalent to or greater than that observed on HA. This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials Park, OH, 2006.     

In situ composite coating of titania-hydroxyapatite on commercially pure titanium by microwave processing

Microwave (MW) processing has been studied as an alternative method of hydroxyapatite (HA) based composite coatings on commercially pure titanium (CPTi) to enhance the bioactivity for orthopaedic and dental implant applications. The coating was formed by processing CPTi metal packed in HA and at 800 W microwave power for 22 min. The composition of the coating was found to be TiO₂ (rutile) as major phase along with HA as minor phase. The MW absorption of non-stoichiometric TiO₂ layer, which was grown during the initial hybrid heating, resulted in sintering of apatite particles interfacing them. The non-stoichiometric nature of TiO₂ was evident from the observed mid-gap bands in ultraviolet-visible diffusive reflectance (UV-VIS-DR) spectrum. The lamellar α structure of the substrate suggests that the processing temperature was above β transus of CPTi (1155 K). The oxygen stabilized α phase whose thickness increased with microwave processing time, was likely to be the reason for the increase in Young's Modulus and hardness of the substrate. The coating induced apatite precipitation in bioactivity test. The osteoblast cell adhesion test demonstrated cell spreading which is considered favourable for cell proliferation and differentiation. Thus, in situ composite coating of titania and HA on CPTi was obtained by a simple one-step process.     

新型微弧氧化钛基种植材料的细胞毒性研究

采用四甲基偶氮唑盐微量酶反应比色法（MTT法）对微弧氧化处理的钛基种植材料的细胞毒性进行研究，并用相差显微镜对细胞形态进行了观察与分析。本研究采用原代培养鉴定后的成骨细胞，与不同材料三维培养，进行种植体材料的细胞毒性研究。结果表明：微弧氧化处理的材料表面细胞形态良好，生长旺盛，细胞计数及MTT测定结果与其它组比较，具有显著性差异，细胞毒性级别优于0级，具有良好的细胞相容性。     

细菌在生物活性钛表面的粘附行为

以经酸碱处理、碱热处理和阳极氧化处理后的生物活性钛材为研究对象,对材料进行了表面形貌分析和表面能的测定,并选用常见感染细菌金黄色葡萄球菌和大肠杆菌为研究菌株,采用体外共培养法培养,通过SEM对细菌的形态、在材料表面的粘附情况和粘附量进行观察,通过MTT法对细菌粘附量进行半定量测定,综合评价生物活性钛的表面结构对细菌增殖和粘附的影响. 结果表明,在3种生物活性钛材料表面,细菌的粘附和增殖受材料表面形貌影响显著,其中碱热处理钛表面和阳极氧化钛表面不利于细菌的增殖和粘附,显示出较好的抑菌性能.     

多孔钛表面改性对其蛋白质吸附行为的影响

考察了酸碱处理多孔钛、碱热处理多孔钛及未改性多孔钛对牛血清白蛋白的等温吸附行为,探讨了多孔钛表面改性对其蛋白质吸附性能的影响。并通过扫描电子显微镜、X射线衍射仪、台阶仪、接触角测量仪等分别考察了3种样品表面形貌、相组成、粗糙度及润湿性等性质。结果表明,表面改性后多孔钛的表面形貌、相组成、粗糙度及润湿性等性质均发生了明显改变,蛋白质吸附性能得到了显著提高。